Harry and Meghan have rebranded their website Sussex.com and while they were about it, changed their children’s surname, which was Mountbatten-Windsor. From now on, Prince Archie, four, and Princess Lillibet, two, are just going to be the Sussexes.

We do not know for certain whether Harry and his wife have also changed their surname, but all the indications would suggest so. A source quoted in The Times says: ‘The reality behind the new site is very simple – it’s a hub for the work the Sussexes do and it reflects the fact the family have, since the King’s Coronation, the same surname for the first time.’

What a moment to choose for this name change. At a time when Harry’s father is undergoing treatment for cancer, and his sister-in-law Kate is far from well, the Californian pair seem to have decided to give out a signal loud and clear: we do not belong to the same family as Charles and William.

The decision is likely to hurt the King for other reasons, too. By dropping the Mountbatten-Windsor name, the Sussexes are effectively expunging Lord Mountbatten who was Charles’s mentor, the man he so revered in his youth, and who was murdered by an IRA bomb.

Prince Philip, too, would surely have been sad at the decision. Lord Mountbatten was also his martinet Uncle Louis.

From now on, Prince Archie, four, and Princess Lillibet, two, are just going to be the Sussexes.

Meghan Markle would not be called Meghan Sussex if she had not come to Britain and chosen to get married in an ostentatious ceremony at Windsor. Pictured in Canada yesterday

There is no doubt that royals get more wound up about surnames than the rest of us. This is because they do not have them in the way we do. They have dynasties.

Philip’s family name, reflecting the various grand dynasties from which he stemmed, was Schleswig-Holstein-Sonderburg-Glucksburg. Since he married Princess Elizabeth only a few years after the Second World War, it is not surprising that the family decided to dump this quadruple-barrelled name, which proclaimed his kinship with the German-speaking states bordering Denmark.

On the wedding certificate, he was called simply Lieutenant P Mountbatten. His first child was Charles Windsor, taking the mother’s ‘surname’.

The name ‘Windsor’ was itself chosen by the royals at the time of the First World War, to stop people remembering that Queen Victoria’s husband had been a German and the family name Saxe-Coburg-Gotha.

Prince Philip did his best, on marrying into the family, to get the Queen to change their name to Mountbatten-Windsor. But Mountbatten – itself an English euphemism for his original family name Battenberg – was still considered too German so soon after the war.

When he discovered the Queen had accepted official advice that they should be called simply Windsor, without the ‘Mountbatten’, it led to his only major public rift with her. And to the famous explosion when Philip, who felt at this moment as if he was being demoted to simply the stud who replenished the royal stock, exclaimed, ‘I’m just a bloody AMOEBA!’

Over the years, Mountbatten-Windsor came back into use. Charles was happy to call his family Mountbatten-Windsor, even though the British Establishment raised eyebrows. Anne and Andrew used Mountbatten-Windsor in their marriage register entries.

The fact is, it was Philip’s name, and its use by Charles’s children is a sign they accept all that the late Duke of Edinburgh did for the late Queen, and for the monarchy. It is also a sign of loyalty to our present King.

By rejecting the name, and rebranding themselves as the Sussexes, this pair of self-advertising egomaniacs have cut themselves off from the King and from the Prince of Wales. Or, anyway, cut themselves off for as long as it suits them.

But, as so often, they want to have their cake and eat it. If they had rebranded themselves Spencer (Harry’s mother’s name) or Markle, we might have some grudging respect for them. If they had taken the name Ragland – the surname of Doria, Meghan’s mother – it would have been a truly feminist gesture.

But, no. They have chosen a name which reflects the fact that Harry is a royal duke. Meghan Markle would not be called Meghan Sussex if she had not come to Britain and chosen to get married in an ostentatious ceremony at Windsor. She is only too happy to have all the trappings of royalty.

Some experts in protocol, both in Britain and America, have questioned whether she should have authorised the use of her own coat of arms on the site. But it is a nice selling point in America where they are in awe of such things. And after parting company with Spotify, as her share price catastrophically dropped, Meghan has signed up with Lemonada Media. She needs all the titles, coats of arms and flummery she can get.

How much more stylish it would have been if she had been true to her professed feminist and republican credentials and simply announced that in future, she’d like us to forget she was a duchess, and be known as former C-list TV actress Meghan Markle.